Question about loss of kidney function?!

Question about loss of kidney function?

last Feb. moms kidney funtion was 3.0 %. went to the er on sat. and kidney funtion is at 3.9%. how does the percentage scale work for kidney function? Please make sure to list sources. Thank you.

3 weeks ago
The doctors wanted to put her on Dyalisis, but she has a DNR, and just wants to go. She had a massive stroke about 4 years ago, and she's been deteriorating ever since. We know she's going to die, we've called hospice, and she's home now. I was just wondering a couple of different things. 1. If her kidneys are functioning at 3.9, how much worse can they get? Does it go up to 5? 10?
and 2. The doctors at the ER told us that she has a month, maybe 2. Does this sound correct?

Again, please list sources. Thanks so much.

My dad went in to kidney failure but he was 92 yrs old I am sorry to tell you it is very painful I took care of him myself with the help of Hospis but he started not drinking and final went into renal failure he didn't last a month.He had of course at his age a DNR also .Spend the time you have left with your mom. Then I buired my mom 2 months later. My prayers are with you and your family Take care of yourself too.